Vertical Charge Research Articles

Evidence of Widely Distributed Time Constants in the Vertical Charge Loss of 3-D Charge-Trap NAND Flash Memories

Evidence of Widely Distributed Time Constants in the Vertical Charge Loss of 3-D Charge-Trap NAND Flash Memories

Synthesis of Ni(OH)2‐g‐C3N4/C Composite by Biological Template for Asymmetric Supercapacitor

Nickel hydroxide (Ni(OH)2) is recognized as a promising material for electrodes in supercapacitors owing to its exceptional theoretical specific capacitance. However, Ni(OH)2 has several drawbacks, including a short cycle life, susceptibility to volume expansion, and poor electrical conductivity. In this work, Ni(OH)2 nanosheets anchored on layered g‐C3N4/C (Ni(OH)2–g–C3N4/C) are designed by biological template induction and a hydrothermal method. Ni(OH)2–g–C3N4/C has unique petal‐like structures, which can provide a vertical charge transport channel to increase reaction potential of the material during the charge–discharge process. The introduction of biomass carbon can solve the problem of the bulk phase accumulation of g‐C3N4 and can also improve the overall conductivity of the composite. Compared to Ni(OH)2 (522 F g−1), g‐C3N4/C (76.2 F g−1), and g‐C3N4 (16 F g−1), the Ni(OH)2–g–C3N4/C‐0.75 (NGC‐0.75) composite exhibits the highest specific capacitance of 1034 F g−1 at 1 A g−1. Furthermore, after 5000 cycles at 5 A g−1, the capacitance of the material is maintained at 85.97%. Meanwhile, the asymmetric supercapacitor based on the NGC‐0.75 shows a high energy density of 18.29 Wh kg−1 at the power density of 400.02 W kg−1 with excellent cyclic stability of 127.45% over 10 000 cycles.

Electrical conductivity of graphene/copper composites at lattice scale

Graphene/copper composites are potential structure-function integrated materials. Different from previous micro-nano scale composites, graphene/copper lattice-scale composites and their effects on electrical conductivity are investigated in this work. Using the first-principles calculation to explore the effects of different numbers of graphene layers on the properties of graphene/copper composites, it is found that with the increase of graphene layer numbers, the interfacial bonding strength improves, but the electrical properties show a decreasing trend due to the electron scattering and increasing Cu–C layer distance. The single-layer graphene/copper composite has the most excellent electrical properties, with the highest density of states at the Fermi level and the most charge transfer. A series of layered-structural composites at lattice scale are screened, and their electrical properties and dynamic stability are also predicted. These composites rely on metallic bonding to connect copper and carbon atoms, most of which show obvious vertical charge transfer and high conductivity, with short Cu–C layer distance and alternating arrangement of metal layers and hexagonal carbon atoms. CuC2 (derived from MgB2) has the highest average conductivity and dynamic stability and can be considered an ideal lattice-scale composite. The development of new lattice-scale composites is significant for the future research of graphene/copper composites.

Magnetic ferroelectric metal in bilayer Fe3GeTe2 under interlayer sliding

The inherent interlayer freedom in van der Waals stacked materials provides an excellent opportunity to investigate ferroelectric-like behavior through interlayer translation. Based on first-principles calculations, we find that the interlayer sliding in Fe3GeTe2 (FGT) bilayer enables the coexistence of polarization, metallicity, and ferromagnetism. We find that the polarization is induced by the uncompensated vertical interlayer charge transfer, and can be switched by an in-plane interlayer sliding. A moderate biaxial strain can reverse the polarization direction of the sliding FGT bilayer. The vertical polarization disentangles with the in-plane conductivity as was previously seen in the sliding ferroelectric WTe2 bilayer. Our work proposes an extremely rare magnetic ferroelectric metal phase that is useful for magnetoelectric and spintronic applications.

Theoretical uncovering of the chalcogen element regulated ESDPT behaviors for 2,5-bis(2-benzoxazolyl)-hydroquinone derivatives.

Inspired by the captivating allure of exquisitely regulated characteristics exhibited by 2-(2-hydroxyphenyl)-benzoxazole and its derivatives in the realms of photochemistry and photophysics, our current endeavor primarily revolves around delving into the intricacies of photo-induced excited state reactions for derivatives of 2,5-bis(2-benzoxazolyl)-hydroquinone (BBHQ). Given the significant impact of chalcogen element doping, herein we predominantly focus on exploring the excited state behaviors of BBHQ-OO, BBHQ-SS, and BBHQ-SeSe fluorophores. Our simulations, resulting from variations in geometry and vertical excitation charge reorganization, reveal atomic-electronegativity-dependent hydrogen bonding interactions and charge recombination induced by photoexcitation that can significantly enhance the excited state intramolecular double proton transfer (ESDPT) reaction for BBHQ-OO, BBHQ-SS, and BBHQ-SeSe fluorophores. By constructing potential energy surfaces (PESs) and identifying transition states (TS), we unveil the ultrafast stepwise ESDPT mechanism due to the low potential barriers. Additionally, by employing heterosubstituted BBHQ-OS and BBHQ-OSe compounds, we rigorously validate the stepwise ESDPT mechanism regulated by chalcogen atomic electronegativity. We sincerely anticipate that the modulation of solvent polarity on excited state behaviors will pave the way for groundbreaking advancements in luminescent materials.

Impact of Gate Voltage on Mobility of Charge Carriers in Conductive Channel of Organic Molecular Semiconductors: Transport Landscape Assessed by Alternating and Direct Current Mode Techniques

AbstractThe gate voltage dependence of the charge carrier mobility is investigated by the microwave resonance technique in transport channels at various organic semiconductors‐insulator interfaces. Although the microwave based measurement is free from the Schottky‐barrier, the vertical charge transport, and the minority carrier trapping, which have been regarded as the origin of the nonlinearity in field effect transistor (FET) measurements, the obtained charge carrier mobility is impacted significantly by the applied gate bias. Atomic force microscopy (AFM) and X‐ray diffractometry (XRD) measurements revealed that the observed nonlinearity indeed originates from the surface disorder in even polycrystalline materials including conjugated polymers. The concerted assessment of the microwave resonance and the FET measurements reveals that 1) injected carriers below the threshold voltage are not trapped despite of the absence of the drain current, 2) the only charge carrier mobility at the 1st layer is assessed by FET measurements, and 3) the threshold voltage of conjugated polymers is relatively low due to the intra‐domain connection through tie molecules.

Effects of substituted chalcogen atoms on excited state proton transfer reaction for 2,5‐bis(benzoxazole‐2‐yl)‐thiophene‐3,4‐diol derivatives: A theoretical study

AbstractMotivated by the captivating allure of exquisitely regulated characteristics exhibited by 2‐(2‐hydroxyphenyl)‐benzoxazole and its derivatives in the domains of photochemistry and photophysics, our current endeavor primarily focuses on delving into the intricacies of photo‐induced excited state reactions for derivatives of 2,5‐bis(benzoxazol‐2‐yl)‐thiophene‐3,4‐diol (BTD). Given the profound impact of chalcogen element doping, our primary focus lies in investigating the excited state behaviors of BTD‐O, BTD‐S, and BTD‐Se fluorophores. Through simulations encompassing variations in geometry and vertical excitation charge reorganization, we unveil atomic‐electronegativity‐dependent hydrogen bonding interactions and photoexcitation‐induced charge recombination that can significantly augment the intramolecular double proton transfer (ESDPT) reaction in the excited state for BTD‐O, BTD‐S, and BTD‐Se fluorophores. By constructing potential energy surfaces and identifying transition state forms, we elucidate the ultrafast stepwise ESDPT mechanism facilitated by the low potential barriers. Moreover, we rigorously validate the chalcogen atomic electronegativity‐driven regulation of the stepwise ESDPT mechanism. We sincerely anticipate that manipulating solvent polarity will pave the way for groundbreaking advancements in luminescent materials.

Explicitly Resolving Lightning and Electrification Processes From the 10–12 April 2019 Thundersnow Outbreak

AbstractThe 10–12 April 2019 thundersnow (i.e., lightning within snowfall) outbreak was examined via ground‐ and space‐based lightning observations and was simulated using a numerical weather prediction model with an explicit electrification parameterization. When compared to observations, the simulation propagated the synoptic snowband two to six hours faster while also exaggerating the 3‐D reflectivity structure. Throughout the event, the simulation produced 1,733 thundersnow flashes which was less than what was observed by ground‐ and space‐based lightning sensors. In general, simulated thundersnow flashes were spatially offset from the largest reflectivities within the synoptic snowband and tended to occur within elevated convection that traversed isentropically along the top of mid‐level frontogenesis. These simulated thundersnow flashes were associated with a tripole charge structure with ice/snow hydrometeors contributing most to the main negative charge region. Both simulated and observed thundersnow flashes initiated in conditionally unstable environments. Lastly, a conceptual model was developed to explain the spatial separation between the largest reflectivities in the snowband and the occurrence of thundersnow. It is hypothesized that the spatial offset of thundersnow initiation from the reflectivity cores within the synoptic snowband arose from a thermal circulation—induced by mid‐level frontogenesis—that advects positively charged ice/snow hydrometeors toward the surface and creates a nearly homogeneous vertical charge structure.

Computational explorations about the solvent-polarity-associated excited state proton transfer behaviors for the novel F-BSD compound.

Inspired by the excellent potential application prospects from the precisely controlled attributes displayed by fluorine-substituted-bis(salicylidene)-1,5-diaminonaphthalene (F-BSD) and its derivatives in the domains of photochemistry and photophysics, our present undertaking predominantly focuses on exploring the complexities of photo-induced excited state reactions for F-BSD fluorophores dissolved in solvents with diverse levels of polarity. Our simulations reveal that the excited state intramolecular double proton transfer (ESIDPT) reaction for F-BSD chemosensor can be significantly regulated by solvent polarity-dependent hydrogen bonding interactions and charge recombination induced by photoexcitation, which result from variations in geometries and vertical excitation charge reorganizations. By constructing potential energy surfaces (PESs), we also demonstrate that the stepwise ESIDPT reaction of F-BSD occurs with alternative dual intramolecular hydrogen bonds (O1-H2···N3 or O4-H5···N6). Interestingly, we affirm polar solvents should be conducive to the first-step of ESIDPT process, while nonpolar solvents are in favor of the second step. We sincerely hope solvent polarity-dependent ESIDPT behavior will pave the way for future design of novel luminescent materials. The molecular geometries were optimized by DFT//TDDFT D3-B3LYP/TZVP theoretical level with IEFPCM solvent model in S0 and S1 states, respectively. This work also explores the energy level of target molecules with the computational vertical absorption spectra by TDDFT. All the simulations were carried out based on Gaussian 16 software. The core-valence bifurcation (CVB) indexes were obtained by using Multiwfn 3.8. Potential energy surfaces were constructed by the DFT//TDDFT D3-B3LYP/TZVP level based on restricted optimization, also the transition state (TS) forms were searched using the same level.

Low‐Power Charge Trap Flash Memory with MoS2 Channel for High‐Density In‐Memory Computing

AbstractWith the rise of on‐device artificial intelligence (AI) technology, the demand for in‐memory comptuing has surged for data‐intensive tasks on edge devices. However, on‐device AI requires high‐density, low‐power memory‐based computing to efficiently handle large data volumes. Here, this study proposes a reliable multilevel, high gate‐coupling ratio memory device with MoS2 channel tailored for high‐density 3D NAND Flash‐based in‐memory computing. The MoS2 channel, featured by its small bandgap and high‐mobility, facilitates reliable memory window of approximately 8 V thanks to erase operation through hole injection. This not only suppresses vertical charge loss but also alleviates the burden on voltage generator circuits, indicating the suitability of MoS2 as channel material for 3D NAND Flash architecture. Additionally, a low‐k (≈2.2) tunneling layer deposited via initiated chemical vapor deposition increases the gate‐coupling ratio, thereby reducing the operating voltage. Utilizing Au nanoparticles as the charge storage layer, MoS2 memory devices show synaptic plasticity with 6‐bit, endurance (104 cycles), read disturbance (105 cycles), and retention times (105 s). Furthermore, device‐to‐system simulations for neural networks based on MoS2‐memory devices have successfully achieved a fingerprint recognition of 95.8%. These results provide the foundation to develop multi‐bit MoS2‐memory devices for AI accelerators and 3D NAND Flash memory.

Origin of Distinct Insulating Domains in the Layered Charge Density Wave Material 1T-TaS2.

Vertical charge order shapes the electronic properties in layered charge density wave (CDW) materials. Various stacking orders inevitably create nanoscale domains with distinct electronic structures inaccessible to bulk probes. Here, the stacking characteristics of bulk 1T-TaS2 are analyzed using scanning tunneling spectroscopy (STS) and density functional theory (DFT) calculations. It is observed that Mott-insulating domains undergo a transition to band-insulating domains restoring vertical dimerization of the CDWs. Furthermore, STS measurements covering a wide terrace reveal two distinct band insulating domains differentiated by band edge broadening. These DFT calculations reveal that the Mott insulating layers preferably reside on the subsurface, forming broader band edges in the neighboring band insulating layers. Ultimately, buried Mott insulating layers believed to harbor the quantum spin liquid phase are identified. These results resolve persistent issues regarding vertical charge order in 1T-TaS2, providing a new perspective for investigating emergent quantum phenomena in layered CDWmaterials.

N-Type ion gel gated vertical organic electrochemical transistors based on benzodifurandione-based Oligo(p-phenylene vinylene)s

Organic electrochemical transistors (OECTs) using aqueous gate dielectrics have garnered significant interest for bioelectronic applications. However, their viability for long-term use in neuromorphic computing and synaptic devices is limited due to their short-term functionality. In this study, we synthesize two benzodifurandione-based oligo (p-phenylene vinylene) polymers, BDOPV-TCNVT and ClBDOPV-TCNVT, and investigate their electrochemical transistor properties using quasi-solid-state ion gel-gated vertical OECTs (v-OECTs). Compared to BDOPV-TCNVT, the chlorinated ClBDOPV-TCNVT demonstrates lower frontier molecular orbitals and easier electrochemical doping. The higher volumetric capacitance of as-spun ClBDOPV-TCNVT (1.94 F cm−3) compared to as-spun BDOPV-TCNVT films (1.49 F cm−3) is mainly attributed to the easier ion infiltration resulting from its lower crystallinity with mixed chain orientation. The quasi-solid-state v-OECTs based on both polymers (as-spun) exhibit transconductance (gm) of 0.06–0.08 mS. Following thermal treatments, the gm gradually decreases for both polymers due to enhanced edge-on ordering with tight interchain packing, hindering ion penetration. Despite the poor electrochemical doping by quasi-solid-state ion gel gated dielectrics, the enlarged area and decreased channel length in v-OECTs (compared to parallel OECTs) can enhance the gm. Further optimization of v-OECTs requires tailored material designs specifically suited for efficient vertical charge transport together with ion infiltration.

Impact of channel thickness on device scaling in vertical InGaZnO channel charge-trap memory transistors with ALD Al2O3 tunneling layer

This study investigates the impact of channel thickness (TCH) variation on memory performance and its physical origins in vertical channel charge trap memory (V-CTM) using InGaZnO (IGZO) channels for X–Y scaling. When the TCH decreased, the subthreshold slope (SS) increased from 0.21 to 0.30 V/dec, while the minimum program voltage decreased from 12 to 8 V, indicating a performance trade-off. The analysis of bulk trap density extracted by SS, density of states distribution, and x-ray photoelectron spectroscopy confirmed an increase in the number of trap states and hydrogen-related defects in the IGZO channel when a thin TCH is employed. As a result, it was expected that the barrier height at the active layer/TL would be lowered during program operations at relatively thin channel. However, the SS would also be degraded due to an increase in sub-gap states, such as OH- and VOH, induced by hydrogen incorporation. The V-CTM with an optimal TCH of 7 nm had a maximum memory window of 5.7 V. The program/erase states were maintained for 106 s before experiencing a 50 % charge loss, and 5-level memory states were verified to be available within a memory window of 3.2 V for 108 s with little degradation. It was noteworthy that the long-term reliability and multilevel implementation could be secured for the V-CTM with a TCH as thin as 7 nm, demonstrating the sound feasibility of its X–Y scaling. This work presents new key parameters and understanding of device integration issues for future 3D structured memory transistors, and aims to contribute to the advancement of memory technologies using oxide semiconductor channels.

A novel MOSFET with lateral–vertical charge coupling for extremely low C gd

A novel MOSFET with lateral–vertical charge coupling (LVCC-MOSFET) is proposed in this paper. Lateral charge coupling is enabled by a metal field plate, lightly doped drain and P-Epi layer to reduce the C gd. Vertical charge coupling is enabled by a shield gate, sinker and P-Epi layer to support a high breakdown voltage (BV) and further reduce the C gd. By combining both lateral charge coupling and vertical charge coupling, which is first proposed in low-voltage power MOSFETs, the trade-off relationship between BV, R on and C gd can be significantly improved. It is verified by both small-signal analysis and transient capacitance simulation that the gate-to-drain capacitance of the proposed LVCC-MOSFET can be reduced by more than 99% without deterioration of BV and R on. The LVCC-MOSFET achieves 93.7% reduction in Q gd, and R on × Q gd is only 0.81 mΩ·nC, which is reduced by 93.9%. Furthermore, E on and E off can be reduced by 73.6% and 53.8%, respectively. The hot carrier injection reliability can be enhanced by reducing the electric field and the impact ionization generation rate near the drain-side gate oxide. Moreover, the LVCC-MOSFET can be feasibly manufactured with compatible fabrication process flow, and only three extra steps are needed.

Effects of UV/O3 and O2 plasma surface treatments on the band-bending of ultrathin ALD-Al2O3 coated Ga-polar GaN

The recently demonstrated semiconductor grafting approach allows one to create an abrupt, low interface-trap-density heterojunction between a high-quality p-type single-crystalline semiconductor (non-nitrides) with n-type GaN. However, due to the surface band-bending from GaN polarization, an energy barrier exists at the grafted heterojunction, which can impact the vertical charge carrier transport. Reducing the energy barrier height is essential for some advanced device development. In this work, we employed UV/O3 and O2 plasma to treat a Ga-polar GaN surface with/without an ultrathin (∼2 nm) ALD-Al2O3 coating and studied the effects of the treatments on surface band-bending. Through XPS measurements, it was found that the treatments can suppress the upward band-bending of the Ga-polar GaN by 0.11–0.39 eV. The XPS results also showed that UV/O3 treatment is an effective surface cleaning method with little surface modification, while O2 plasma causes a strong oxidation process that occurs inside the top layer GaN.

High Electrical Conductivity and Hole Transport in an Insightfully Engineered Columnar Liquid Crystal for Solution-Processable Nanoelectronics.

Discotic liquid crystals (DLCs) are widely acknowledged as a class of organic semiconductors that can harmonize charge carrier mobility and device processability through supramolecular self-assembly. In spite of circumventing such a major challenge in fabricating low-cost charge transport layers, DLC-based hole transport layers (HTLs) have remained elusive in modern organo-electronics. In this work, a minimalistic design strategy is envisioned to effectuate a cyanovinylene-integrated pyrene-based discotic liquid crystal (PY-DLC) with a room-temperature columnar hexagonal mesophase and narrow bandgap for efficient semiconducting behavior. Adequately combined photophysical, electrochemical, and theoretical studies investigate the structure-property relations, logically correlating them with efficient hole transport. With a low reorganization energy of 0.2eV, PY-DLC exhibits superior charge extraction ability from the contact electrodes at low values of applied voltage, achieving an electrical conductivity of 3.22 × 10-4 Sm-1, the highest reported value for any pristine DLC film in a vertical charge transport device. The columnar self-assembly, in conjunction with solution-processable self-healed films, results in commendably elevated values of hole mobility (≈10-3 cm2V-1s-1). This study provides an unprecedented constructive outlook toward the development of DLC semiconductors as practical HTLs in organic electronics.

Electrical Properties of Vertical Dominant Charge Structures Observed in Corsican Thunderstorms With a LMA

AbstractLightning characteristics of Corsican storms with different charge structures are investigated in this study. Observations of an LMA network are used to document the total lightning activity. Complementary lightning observations of the lightning detection network Météorage are also used. A clustering algorithm is used to build a database of electrical cells from June to October 2018. A method is also applied to infer the vertical charge structure, as dominant dipoles, per 10‐min period for each electrical cell. As an example, one cell recorded in July 2018 is discussed. The cell database is then presented as well as the main electrical properties according to the dominant charge structures. For instance, the higher in altitude the dominant dipole, the higher the flash rate. Overall, dominant negative dipole are observed for 25% of the 10‐min periods and can be separated into two categories: (a) low altitude negative dipole class dominated by negative cloud‐to‐ground (CG) flashes with a main positive layer located between 2 and 4 km height and (b) high altitude negative dipole class, dominated by negative intracloud (IC) with a main positive layer at 5 km height. Dominant positive dipole can also be separated into two categories with (a) a dominant positive dipole located between 4.5 and 10 km high, −CG dominance, weak flash rate and (b) higher altitude dominant positive dipole, +IC dominance and a larger +CG fraction. The synergistic use of LMA and Météorage observations independently gives a rational type and polarity classification with regard to the vertical charge structure.

A–D–A'–D–A type nonfused ring electron acceptors for efficient organic solar cells via synergistic molecular packing and orientation control

AbstractNonfused ring electron acceptors (NFREAs) are promising candidates for future commercialization of organic solar cells (OSCs) due to their simple synthesis. Still, the power conversion efficiencies (PCEs) of NFREA‐based OSCs have large room for improvement. In this work, by merging end group halogenation and side chain engineering, we developed four A–D–A'–D–A type NFREAs, which we refer to as EH‐4F, C4‐4F, EH‐4Cl, and C4‐4Cl. Single crystal X‐ray diffraction revealed that multiple intermolecular S···F interactions between cyclopentadithiophene and 5,6‐difluoro‐3‐(dicyanomethylene)indanone could cause an unfavorable dimer formation, leading to ineffective π–π stackings in EH‐4F and C4‐4F, whereas no such dimer was found in EH‐4Cl and C4‐4Cl after replacing with 5,6‐dichloro‐3‐(dicyanomethylene)indanone. Moreover, although the shorter n‐butyl side chain resulted in a closer molecular packing in C4‐4Cl, EH‐4Cl (2‐ethylhexyl substitution) with proper crystallinity exhibited enhanced face‐on orientation in thin film, which is favorable for vertical charge transport and further reducing charge recombination. As a result, a PCE of 13.0% is obtained for EH‐4Cl‐based OSC with a fill factor of 0.70. This work highlights the importance of molecular packing and orientation control toward future high‐performance A–D–A'–D–A type NFREAs.

Substitution of lead with tin suppresses ionic transport in halide perovskite optoelectronics.

Despite the rapid rise in the performance of a variety of perovskite optoelectronic devices with vertical charge transport, the effects of ion migration remain a common and longstanding Achilles' heel limiting the long-term operational stability of lead halide perovskite devices. However, there is still limited understanding of the impact of tin (Sn) substitution on the ion dynamics of lead (Pb) halide perovskites. Here, we employ scan-rate-dependent current-voltage measurements on Pb and mixed Pb-Sn perovskite solar cells to show that short circuit current losses at lower scan rates, which can be traced to the presence of mobile ions, are present in both kinds of perovskites. To understand the kinetics of ion migration, we carry out scan-rate-dependent hysteresis analyses and temperature-dependent impedance spectroscopy measurements, which demonstrate suppressed ion migration in Pb-Sn devices compared to their Pb-only analogues. By linking these experimental observations to first-principles calculations on mixed Pb-Sn perovskites, we reveal the key role played by Sn vacancies in increasing the iodide ion migration barrier due to local structural distortions. These results highlight the beneficial effect of Sn substitution in mitigating undesirable ion migration in halide perovskites, with potential implications for future device development.

Bistable Resistive Memory Switches fabricated by Floating Thin Films of Conjugated Polymers

The layer-by-layer (LBL) fabrication of conjugated polymer (CPs) thin films while preserving their microstructural features by solution processing is highly desired for compact and flexible electronic circuits. However, it is cumbersome and challenging owing to the unavoidable damage to the underlying layers. To circumvent this issue, the unidirectional floating-film transfer method (UFTM) was utilized for the LBL fabrication of oriented CP thin films on the orthogonal liquid surfaces. Further, resistive bistable memory switches were fabricated by sandwiching a layer of metal nanostructures between the LBL-fabricated oriented CP thin films. The resistive switching phenomena were realized by utilizing the applied bias-dependent charge trapping, holding, and recombination on the available states at vacuum-deposited aluminum nanostructures. The effect of CP backbone conformation on the vertical charge transport was also analyzed via a comparative study of three thiophene-based polymers namely RR-P3HT, PBTTT, and PTB-7. It was revealed that CPs with relatively fewer hydrophobic side chains was more favorable for the facile vertical charge transport due to its preferred face-on conformation on the hydrophilic liquid substrate used in UFTM. It was demonstrated that a non-volatile bistable resistive memory switch fabricated using UFTM-processed oriented thin films of PTB-7 exhibited a remarkably high on-off ratio of 1.5 × 106 with high durability.